Many puzzles have been invented which involve the assembly of polygonal tiles on a horizontal surface to form one or more desired polygonal figures. The most popular puzzle of this type, known as the tangram, involves the assembly of five triangular tiles and two quadrilateral tiles to form a square. The proportion between any two sides of any two tiles is an integral power of the square root of two. Many other shapes can be formed from these seven tiles, providing hours of amusement.